1. Field of the Invention
The present invention relates to a wireless mobile station and a wireless communication system with the same. More specifically, the present invention relates to a wireless mobile station in a wireless communication system, which employs transmission diversity, and a wireless communication system with the same.
2. Description of the Related Art
Conventionally, transmission diversity in which more than two transmission channels for transmitting downstream signals are set and channel estimation have been used in the CDMA wireless system in order that the downstream signals transmitted from a base station can be received in a wireless mobile station such as a mobile phone with good sensitivity.
However, in the conventional technique, for the purpose of antenna detection, operations such as comparisons for all of the 16 kinds of vectors composed of two elements, that is, phase and amplitude of the downstream signals are performed in conformity with the rule in a plurality of fingers in the CDMA wireless mobile station. Therefore, the amount of arithmetic operation performed in each of the fingers becomes enormous in some cases.
In the case where the amount of arithmetic operation becomes enormous, the lifetime of an electric battery used in the CDMA wireless mobile station becomes short. Therefore, it is necessary to increase the size of the battery. For its prevention, it is desired to simplify the above-mentioned arithmetic operation.
In addition, in the CDMA wireless mobile station, an FSM signal is generated in order to control the strength of the downstream signal, and the generated signal is fed back to the base station. However, if the FSM signal is overlapped with a noise or the FSM signal is deteriorated during the transmission through a transmission channel, the signal different from the original FSM signal is received in the CDMA wireless base station. In such a case, since the FSM signal used in the CDMA wireless base station and the FSM signal used in the channel estimation in the CDMA wireless mobile station are not equal to each other, the reception characteristics thereof are deteriorated in some cases. As a result, it becomes necessary to perform the antenna detection.